chat.js

// initialize Firebase
var config = {
  apiKey: "AIzaSyDnQLFM5Hib9_5AZIapEIVO4NSFTnRYs5E",
  authDomain: "wbd3-fap.firebaseapp.com",
  databaseURL: "https://wbd3-fap.firebaseio.com",
  storageBucket: "wbd3-fap.appspot.com",
  messagingSenderId: "655114709739",
};
firebase.initializeApp(config);

const messaging = firebase.messaging();

messaging.requestPermission()
  .then(() => {
    console.log("Permission Granted");
  })
  .catch(function(err) {
    console.log('Unable to get permission to notify.', err);
  });

  // Get Instance ID token. Initially this makes a network call, once retrieved
  // subsequent calls to getToken will return from cache.
  messaging.getToken()
  .then(function(currentToken) {
    if (currentToken) {
        var scope = angular.element(document.getElementsByTagName("body")).scope();
        scope.sendTokenToServer(currentToken);
        scope.$apply();
      // sendRegistrationToServer(currentToken);
      // updateUIForPushEnabled(currentToken);
      console.log(currentToken);
    } else {
      // Show permission request.
      console.log('No Instance ID token available. Request permission to generate one.');
      // Show permission UI.
      // updateUIForPushPermissionRequired();
      // setTokenSentToServer(false);
    }
  })
  .catch(function(err) {
    console.log('An error occurred while retrieving token. ', err);
    // showToken('Error retrieving Instance ID token. ', err);
    // setTokenSentToServer(false);
  });

  // Callback fired if Instance ID token is updated.
messaging.onTokenRefresh(function() {
  messaging.getToken()
  .then(function(refreshedToken) {
    console.log('Token refreshed.');
    console.log(refreshedToken);
      var scope = angular.element(document.getElementsByTagName("body")).scope();
      scope.sendTokenToServer(currentToken);
      scope.$apply();
    // Indicate that the new Instance ID token has not yet been sent to the
    // app server.
    // setTokenSentToServer(false);
    // Send Instance ID token to app server.
    // sendTokenToServer(refreshedToken);
    // ...
  })
  .catch(function(err) {
    console.log('Unable to retrieve refreshed token ', err);
    // showToken('Unable to retrieve refreshed token ', err);

  });
});

  messaging.onMessage(function(payload) {
    console.log("Message received. ", payload);
    angular.element(document.getElementsByClassName('chat-box')[0]).scope().insertMsg(payload);
    angular.element(document.getElementsByClassName('chat-box')[0]).scope().$apply();
    // ...
  });